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Balasore, India

Tamakuwala J.B.,Integrated Test Range
2012 National Conference on Communications, NCC 2012 | Year: 2012

LDPC codes are among the few FEC schemes that have been used for distributed data compression schemes, like the Slepian-Wolf encoding. An LDPC code having good degree distribution polynomials, along with a large girth and large minimum distance, can compress close to the Slepian-Wolf limit. In this paper, we describe a method to choose good degree distribution polynomials and the corresponding code construction for binary sources. Furthermore, the performance of the proposed compression scheme is also demonstrated. In selected cases, we improve the best schemes reported in literature. © 2012 IEEE.


Hazra S.,Integrated Test Range | Das J.,Indian Institute of Technology Kharagpur | Bandyopadhyay P.P.,Indian Institute of Technology Kharagpur
Materials Chemistry and Physics | Year: 2015

A mechanical mixture of alumina and pulverized zircon sand in 3:2 M ratio has been plasma sprayed to obtain mullite coating. Thereafter, the top layer of the coating has been remelted using laser. The presence of a mullite phase in the as-sprayed and laser remelted coatings has been confirmed qualitatively using X-ray diffraction. Both as-sprayed and laser remelted coatings have been characterized for their microstructure, hardness and porosity. The ultrafine grain structure of the coating produced by rapid quenching has been analyzed using transmission electron microscope. Presence of a mullite phase in the coatings has also been confirmed using small angle electron diffraction. Laser remelting has resulted in an appreciable reduction in porosity and increase in hardness in the coatings. © 2015 Elsevier B.V. All rights reserved.


Hazra S.,Integrated Test Range | Bandyopadhyay P.P.,Indian Institute of Technology Kharagpur
Materials and Design | Year: 2012

A set of plasma sprayed coatings were obtained from three alumina based top coat and two bond coat powders. Scratch test was undertaken on these coatings, under constant and linearly varying load. Test results include the lateral force data and scanning electron microscope (SEM) images. Failure occurred by large area spallation of the top coat and in most cases tensile cracks appeared on the exposed bond coat. The lateral force showed an increasing trend with an increase in normal load up to a certain point and beyond this, it assumed a steady average value. The locations of coating spallation and occurrence of maximum lateral force did not coincide. A bond coat did not show a significant role in determining the scratch adhesion strength. © 2011 Elsevier Ltd.


Hazra S.,Integrated Test Range | Bandyopadhyay P.P.,Indian Institute of Technology Kharagpur
Surface and Coatings Technology | Year: 2016

Mullite was obtained by plasma spraying a mechanical mixture of alumina and zircon sand mixed in 3:2 M ratio. The following parameters were varied during coating deposition: arc current, secondary gas, i.e., hydrogen flow rate, stand-off distance (SOD) and angle of powder injection. These parameters were chosen since they significantly affect powder heating and consequently, mullite formation. Laser surface treatment was undertaken on a couple of selected coatings. The amount of mullite formed in the coating was estimated using Rietveld analysis of the X-ray diffraction patterns of the as-spayed and laser treated coatings. The effects of these parameters on coating hardness and porosity were also taken into account. Finally the mullite yield was correlated with coating porosity and hardness. © 2016 Elsevier B.V.


Das S.,Integrated Test Range | Nayak G.C.,Indian School of Mines | Sahu S.K.,Integrated Test Range | Routray P.C.,Integrated Test Range | And 2 more authors.
Polymer - Plastics Technology and Engineering | Year: 2015

A novel core–shell-structured nanocomposite material based on titanium dioxide-coated magnetite and Ni-ferrite has been prepared for RADAR absorbing application in a X-band region. The coating of magnetic particles with TiO2 was carried out by in situ hydrolysis of titanium tetrabutoxide, and the composite absorber sheets were prepared with epoxy resin. The morphological characterization of the magnetic particles was studied with field emission scanning electron microscope, transmission electron microscope, X-ray diffraction, and vibrating sample magnetometer analysis techniques. The measurement results confirmed the coating of magnetic particles with TiO2 and reduction of the magnetization of magnetite and Ni-ferrite nanoparticles compared with the uncoated ferrite nanoparticles. Distribution of particle inside the matrix was studied with scanning electron microscope. Microwave absorption study in X-band (8–12 GHz) region was carried out with vector network analyzer. Results showed reflection loss values of −26.5 db at 9.08 GHz for the magnetite coated with titanium dioxide/conducting carbon black containing sample which increased to −45.7 db at 9.13 GHz for the Ni-ferrite coated with TiO2/conducting carbon black formulation. It was observed that coating of magnetic particles resulted in the improvement in the microwave absorption. © Taylor & Francis Group, LLC.

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